Loud speaker structure



May 12, 1964 A. L. COEN 3,133,162

LOUD SPEAKER STRUCTURE Filed Sept. 6, 1961 2 Sheets-Sheet 1 60 26' 4 6g UML 22 [W 2 INVENTOR.

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@w/zeyl May 12, 1964 A. L. COEN 3,133,162

LOUD SPEAKER STRUCTURE Filed Sept. 6, 1961 2 Sheets-Sheet 2 fdaJC United States Patent 3,133,162 LOUD SPEAKER STRUCTURE Aldo L. Coen, 1640 E. 50th St, Chicago 15,111. Filed Sept. 6, 1961, Ser. No. 136,361 9 Claims. (Cl. 1'79-119) This invention relates generally to audio reproducing devices, and more particularly, relates to structural improvements in a loudspeaker of the permanent magnet type which enable the field structure to be separated from the speaker basket assembly without destroying or mutilating the same. I e

In the permanent-magnet type of loudspeaker, a strong magnetic field is established between pole pieces by means of a powerful permanent-magnet. The magnet usually includes a magnet housing or pot, as frequently referred to in the trade, having a soft-iron core disposed therein, the magnet housing being rigidly secured to a metal basket which mounts a cone to which the voice coil is secured. The magnetic field of very high flux density is concentrated in an air gap between a highly paramagnetic core and magnet housing, and the voice coil is mounted in the air gap so that its wire turns traverse the principal lines of force of the magnetic field. The flow of AC. signal currents through the voice coil causes the coil to move axially in accordance with said signal currents so that the cone attached to the coil likewise is moved in accordance with such signal currents to set up sound waves in the air. A corrugated diaphragm or spider is attached to the cone to keep it properly centered and supported in place.

3,133,162 Patented May 1 2, 1964 quality permanent-magnet type speaker. However, the nature of said connection is such that, if desired, the magnet housing and speaker basket readily can be separated without requiring the entire speaker structure to be torn apart. Thus, after the speaker structure has been completely assembled and tested, if a reject product is en-, countered, the magnet housing can be separated safely from the metal basket, the magnet demagnetized and the undesirable debris blown out or otherwise removed, the magnet again magnetized and thereafter, assembled to the a same basket mounting the cone and previously used com- In the manufacture of such magnetic speaker, it has become lodged in the magnet housing during assembly of the loudspeaker, buzzing and noise resulted so as to render the entire speaker unsatisfactory or rejected. Great care and precaution have tobe taken in order to avoid such undesirable and inadvertent entry of debris into the mag net housing, etc. Although a relatively small percentage of unsatisfactory or rejected speaker structures ordinarily resulted in normal production, where production is in large and significant volumes, even a relatively small percentage of rejects can become an expensive additional cost factor. p j V Attempts at salvaging rejected or sub-standard speaker products have been reduced to dismantling the speaker structure merely to recover the magnet which is the most expensive component of the loudspeaker. The reason for .thisis traceable to the requirement in such speakers that the magnet housing or pot be rigidly and precisely connected to the metal basket. Such connection is permanent in nature by reason of the operational characteristics desired for the speaker. Consequently, in order torecover the magnet, it has heretofore been required to tear the speaker apart, thus-destroying or rendering impossible to use again the components of the speaker other than the magnet. Obviously, this is'quite acostly procedure,

especially where large volumes of loudspeakers are being ponents of the speaker. However, if the speaker assembled does operate satisfactorily, theconnection between the magnetic housing and the metal basket is of such a character as is equivalent to the permanent securement therebetween heretofore employed in the speaker assembly. In other words, the invention provides for achieving a completely assembled speaker structure which after testing and found to be satisfactory, can be used without further work being entailed thereon, and yet which does permit the field structure to be separated from the speaker basket assembly without damaging said speaker basket.

Accordingly, it is a primary object of the invention to provide an audio reproducer structure of the character described which enables the foregoing advantages, as well as others, to be achieved.

An important object of the invention is to provide a permanent-magnet type loudspeaker of the character described which includes a field structure and metal basket co-operatively connected together by means of a separable juncture which is satisfactory for operation of the speaker after same has been completely assembled, but which ,connection can be selectively separated and remade as desired Without destroying or mutilating other components of the loudspeaker.

Another important object of the invention is to provide a loudspeaker structure of the character described which includes a'magnet housing and speaker basket connected together by separable coupling means, said coupling means being separable by limited rotary movement of the magnetic housing and speaker basket one relative to the other for separating and for remaking the connection repeatedly.

Another important object of the invention is to provide a speaker structure of the character described in which said metal speaker basket is provided with a plurality of notches circumferentially spaced apart around a central opening in the basket, and said magnet housing is pro vided with a plurality of flanged deformations in the up per end thereof adapted to be aligned with said notches and rotated one relative to the other for making and breaking said connection repeatedly without destroying or mutilating other components of the speaker structure.

Another object of the invention is to provide such separable coupling of the magnet housing and speaker basket of a permanent-magnet type loudspeaker which can be as heretofore employed, and which is suitable fora substantially universal use in connection with the manufacture of such type speakers. l

The foregoing and other objects of the invention will become apparent as the description therof evolves. A preferred embodiment of the invention has been described in detail in the specification and illustrated in the accompanying drawings.

It is contemplated that minor varia tions in the arrangement, size, proportion and construction of the various parts thereof may occur to the skilled artisan without departing from the spirit or sacrificing any of the advantages of the invention.

In the drawings:

FIG. 1 is a fragmentary sectional view taken through a portion of the loudspeaker structure embodying the invention.

. FIG. 2 is a side elevational view of the magnet housing employed in the loudspeaker structure embodying the invention.

FIG. 3 is a top plan view of said magnet.

FIG. 4 is a plan view of the speaker basket to which the magnet housing is secured by means of a separable connection or juncture in accordance with the invention.

FIG. 5 is a fragmentary sectional view taken through the speaker structure and on an enlarged scale to show the separable connection between the magnet housing and speaker basket, various component parts of the speakar being omitted for purposes of clarity.

FIG. 6 is a top plan view of a metal speaker basket and magnet housing such as used in the speaker structure with the basket and housing completely assembled.

FIG. 7 is a fragmentary top plan view similar to FIG. 6 with the magnet housing having been rotated relative to the metal basket to a position for unlocking the connection therebetween.

FIG. 8 is a fragmentary plan view similar to FIG. 6 and on an enlarged scale to show the metal basket and magnet housing again locked one with the other. I

Referring now to the drawings, the reference character 10 designates generally a loudspeaker of the permanentmagnet type with which the invention is concerned. It will be appreciated that all of the component parts of speaker 10 are conventional and assembled in a well known manner and departure from the known parts illustrated may occur to the skilled artisan. The reference character 12 designates generally a completed field structure which includes the permanent magnet of the loudspeaker 10 and the reference character 14 designates the speaker basket to which the field structure 12 is connected in the advantageous manner provided for by the herein invention, these components of the speaker 10 being novel.

Insofar asit was heretofore known for suchspeaker structures, the field structure 12 may be seen to include a generally cylindrical magnet housing 16 having an integral circular bottom wall 18 provided with an interior flat surface 20. The upper end of the magnet housing or pot is provided with an annular exterior shoulder 22, and an annular interior surface 24 which is substantially uniform commencing from the upper end to a point adjacent the bottom wall 18 of the magnet housing. The upper end of the housing 16 has an axially facing end surface 26 of circular configuration.

At this point, it may be understood that a magnet housing or pot 16 is a conventional component of such speakers and therefore, that the magnet housing illustrated may be modified to include other structural features as well within the purview of such permanent-magnet dynamic type speakers. There are certain critical dimensions of the field structure 12 which are desirable for eflicient and proper operation of the loud speaker. These include accurate parallelism between the interior flat face 20 of the bottom wall 18 and the annular shoulder 22 and an accurate coaxial relationship between the cylindrical interior of the upper end of the housing and the shoulder 22. Although not as critical, it is desirable that the upper end face 26 be parallel with the fiat face 20 of the wall 18.

The speaker basket 14 generally is formed of a sheet metal member in the form of a framework or cage to protect the paper cone 3t) and support the outer periphery thereof. As seen in FIG. 4, the metal basket 14 is a generally rectangular metal plate having an island-like medial formation 32 provided with a coaxial opening 34 of predetermined diameter so as to permit engagement of the basket upon the shoulder 22.

A paramagnetic core 36 is coaxially mounted on the surface 20 of housing 16 and the diameter of the pole end 38 is somewhat less than the inner diameter of the cylindrical surface 24 so as to provide a narrow gap or annular space 40 between the core 36 and the magnet housing. This gap or annular space 40 is very narrow and the magnetic field is concentrated in this space. As seen in FIG. 1, the gap 40 is exaggerated in size for purposes of clarity. The iron core 36 may be cemented to the bottom wall 18 or as shown in FIG. 1, the interior annular surface 24 may be inwardly crimped to engage the lower end of the core as indicated at 42 to hold the core in place on the interior of the magnet housing 16.

A varnished resilient buckram or linen spider 44 provided with molded concentric grooves is cemented to the interior of the metal basket and the inner end or apex of the cone 30 is secured to the corrugated diaphragm 44 at 46. A short cylindrical tube 43 of relatively thin fibrous material is secured to the cone 3t at 50 which extends into the gap 40 coaxial with the pole piece 38. The tube 48 serves as the former for the voice coil 52, the wire turns of the voice coil being arranged on the former 48 so that the magnetic field created by the wire as signal currents pass therethrough will intersect the lines of force extending across the gap 40 between the pole piece and the opposite facing surface 24 of the magnet housing. The wires 54 from the voice coil are shown extending into the cone and out through the wall thereof for connection to the source of audio frequency current. A felt disc 56 is arranged on the interior of the cone overlying the apex thereof, to prevent entry of undesirable dust. The spider or diaphragm 44 holds the cone in place relative to the former 48 and serves to center the cone.

Only after the speaker structure 10 has been fully assembled to the condition shown in FIG. 1, can the magnet 36 be magnetized and the loud speaker tested. If any dirt or metal particles have entered the housing between the inner wall 24 thereof and the adjacent core 36, undesirable buzzing and noise occur during operation so as to render the speaker structure unsatisfactory. Heretofore, the magnet housing 12 has been rigidly and permanently secured to the metal basket 14 by staking, for instance, so that in order to salvage the expensive magnet of the loud speaker 10, it was necessary to substantially destroy or mutilate the speaker basket and the other components supported and secured thereon in order to recover the magnet 36.

The magnet housing 16 as seen in FIGS. 2 and 5 has an annular coaxial neck or flange 6t) protruding beyond the annular shoulder 22. The outside diameter of the neck portion 60 is slightly smaller than the diameter of the central opening 34 in the metal basket 14 as seen in FIG. 5. The central opening 34 is provided with a plurality of notches or recesses'62 circumferentially spaced apart along the marginal rim of said opening. As seen in FIG. 4, said recesses 62 are substantially equally spaced apart approximately four of such recesses being utilized. The recesses need be only of shallow depth.

At the time of initial assembly of a speaker structure, the annular neck or flange may be entirely uniform and regular in configuration, that is to say, lacking the protruding formations 64 seen in FIG. 2. In the assembly procedure, the protruding annular flange 60 is inserted into the opening 34 with flange 22 abutting the basket and staked into position at selected locations intermediateadjacent pairs of recesses 62. In the staking operation, portions of the end face 26 of the flange 60 are deformed'to provide the outwardly protruding or overhanging formations 64 which are caused to bear against the annular land portion 68 of the basket in tight frictional engagement therewith.- Likewise, adjacent formations 64 are spaced apart ninety degrees corresponding to the spacing between adjacent recesses 62. Thus, the staking is performed between notches 62 so as to bear against the basket. Further, any burrs or protuberances along the marginal rim of the opening 34 will assist in providing a tight connection between said housing and speaker basket.

Referring to FIG. 5, the staking operation results in outwardly protruding lug-like or bayonet type formations 64 which have overhang, as'seen at 70. The free extremity 72 of each formation usually is rounded and the formation 64 bears tightly against the metal basket, perhaps even slightly deforming same at the land portion subtending the formation 64. The land portion 68 is clamped between formation 64 and shoulder 22.

Referring to FIG. 6, the completed assembly of the field structure 16 and the metal basket 14 is illustrated and the juncture therebetween is for all practical purposes to be considered of a rigid character.

If upon magnetizing the magnet and testing of the speaker structure, it is determined that the speaker buzzes and is noisy, separation of the magnet and speaker basket readily'is accomplished. Initially, the magnet is demagnetized. By means of a wrench or pliers, the housing 16 can be rotated about forty-five degrees relative to the metal basket 14 until each of the formations 64 is aligned with a notch 62, as seen in FIG. 7. The housing then can be withdrawn readily from opening 34, and blown or otherwise cleaned out. Thereafter, the housing 16 can be reinserted with a wrench or pliers into opening 34, twisted or rotated until the two components are locked together as seen in FIG. 8. The magnet then is magnetized and the speaker can be tested. It will be apparent that any burrs, for instance, present along the marginal edge of opening 34 may be wiped off during relative rotary movement between basket 14 and housing 16 or further assist to hold the members together tightly.

It will be appreciated from the forgoing description that the invention provides for a positive, rigid and perma nent-type juncture between the magnet housing 16 and the speaker basket 14 which is entirely satisfactory for operation of the speaker. However, in the event the speaker does not operate properly because dirt or metal particles have entered the magnet housing during assembly thereof, the magnet housing and speaker basket can be separated readily without damage to other'speaker basket parts. Further, the magnet housing thereafter can be reassembled to the same speaker basket. Thus, previous losses due to the procedure for recovering the magnets of such speakers are entirely avoided. Advantages of the invention can be realized regardless of the particular type of magnet housing used.

Although the invention has special advantages in connection with permanent-magnet type loudspeakers because of the expense of the permanent magnet, it is conceivable that the invention also might be useful for other types of loudspeakers where it is desired to providefor convenient separation of the yoke and speaker basket for any reason whatsoever.

The invention has been pointed out in the claims hereto appended in language intended to be liberally construced.

I claim:

1. In a loudspeaker having a metal speaker basket provided with a medial co-axial opening therein surrounded by a marginal rim and a magnet housing having the upper end thereof adapted to be engaged in said opening and staked to the basket to effect a permanent-type connection therebetween, said housing having flanged formations integral with the upper end thereof overhanging and matingly engaging said marginal rim and said basket having means adapted to be aligned with said formations by means of a limited rotary movement of the housing and basket one relative to the other selectively to permit axial separation of the housing and basket, and subsequent connection of said basket and housing.

2. In a loudspeaker having a metal speaker basket provided with a medial co-axial opening therein surrounded by a marginal rim and a magnet housing having the upper end thereof adapted to be engaged in said opening and staked to the basket to effect a permanent-type connection therebetween, said housing having flanged formations integral with the upper end thereof overhanging and matingly engaging said marginal rim and said basket having means adapted to be aligned with said formations by means of a limited rotary movement of the housing and basket one relative to the other selectively to permit axial separation of the housing and basket, and subsequent connection of said basket and housing, said means comprising said marginal rim having a plurality of circumferentially spaced apart recesses therein each adapted to be aligned with a flanged formation for effecting said separation but normally not aligned said flanged formation whereby said permanent-type connection is realized.

3. In a structure as described in claim 1 in which said means comprise said marginal rim having a plurality of recesses equally spaced apart along the perimeter thereof and said flanged formations are likewise spaced apart along said upper end of the housing normally not aligned with said recesses.

4. In a permanent-magnet type audio reproducing device, a field structure including a magnet housing having an annular neck at the upper end thereof and an annular exterior shoulder spaced from the end face of said neck, a sheet metal speaker basket having a central coaxial opening therein, said neck being engaged through said opening and having flanged formations integral with the end face thereof normally overhanging and frictionally engaging portions of the basket surrounding said opening therein for coupling the basket and housing together in a permanent-type connection supported upon said shoulder, said basket having means spaced apart along the said portion of the basket adapted to underlie said formations so as to permit axial separation of the basket and housing, albeit being normally displaced laterally relative said formations for coupling said basket and housing together.

5. In a structure as described in claim 4 in which said flanged formations comprise deformations in the end face of said neck and said means comprise recesses in the marginal rim of said opening, said formations and recesses adapted to be brought into registry respectively by limited rotary movement of the housing relative to the basket.

6. In a structure as described in claim 4 in which said flanged formations comprise deformations in the end face of said neck circumferentially spaced apart a substantially equal angular distance, and said means comprise recesses in the marginal rim of said opening likewise so spaced apart, the number of formations being equal to the number of recesses, said recesses and formations adapted to be brought into registry by limited rotary movement of the basket relative to the housing.

7. In a structure as described in claim 6 in which said formations and recesses are spaced apart respectively approximately ninety degrees.

8. In a loudspeaker having a magnet housing adapted to be staked to a sheet metal speaker basket in a permanent-type coupling thereof, a sheet metal basket having an annular land portion surrounding a central axial opening therethrough, said land portion having a plurality of recesses circumferentially spaced apart and opening into said central opening, said basket adapted to be selectively rotated relative to the housing to align said recesses and staking formations respectively to permit axial separation of the housing and basket and. subsequent connection thereof.

9. In a permanent-magnet type audio reproducing device, a field structure including a magnet housing having a permeable core on the interior thereof, said housing having an annular neck at the upper end thereof and an annular shoulder spaced from said upper end of greater diameter than said neck, a speaker basket having a coaxial opening therein, said neck being matingly engaged within said opening With said shoulder engaged against one surface of the basket, said neck having integral flanged formations bearing against the opposite surface of the basket for locking the basket and housing together in a rigid connection, said basket having means cooperative with said flanged formations for selectively separating the basket and housing and locking same together repeatedly by limited rotary movement of one relative the other.

References Cited in the file of this patent UNITED STATES PATENTS Hardisty Apr. 25, 1933 Rowe Dec. 24, 1935 Charlesworth Apr. 1, 1952 Zuerker et al V July 7, 1959 FOREIGN PATENTS Germany July 14, 1960 Disclaimer and Dedication 3,133,162.-AZ(Z0 L. 006%, Chicago, Ill. LOUDSPEAKER STRUCTURE. Patent dated May 12, 1964:. Disclaimer and dedication filed Aug. 7, 1973, by the assignee, Alpha Pwoducts, law. Hereby disclaims and dedicates t0 the Public the remaining term of said patent.

[Ofiioz'al Gazette Febmawy 19,197'4J Disclaimer and Dedication 3,133,162.-Ald0 L. 00%, Chicago, 111 LOUDSPEAKER STRUCTURE. Patent dated May 12, 1964. Disclaimer and dedication filed Aug. 7 197 3, by the assignee, Alpha Products, Inc. Hereby disclaims and dedicates to the Public the remaining term of said patent.

[Oyficz'al Gazette Febmawg 19,1974] 

1. IN A LOUDSPEAKER HAVING A METAL SPEAKER BASKET PROVIDED WITH A MEDIAL CO-AXIAL OPENING THEREIN SURROUNDED BY A MARGINAL RIM AND A MAGNET HOUSING HAVING THE UPPER END THEREOF ADAPTED TO BE ENGAGED IN SAID OPENING AND STAKED TO THE BASKET TO EFFECT A PERMANENT-TYPE CONNECTION THEREBETWEEN, SAID HOUSING HAVING FLANGED FORMATIONS INTEGRAL WITH THE UPPER END THEREOF OVERHANGING AND MATINGLY ENGAGING SAID MARGINAL RIM AND SAID BASKET HAVING MEANS ADAPTED TO BE ALIGNED WITH SAID FORMATIONS BY MEANS OF A LIMITED ROTARY MOVEMENT OF THE HOUSING AND BASKET ONE RELATIVE TO THE OTHER SELECTIVELY TO PERMIT AXIAL SEPARATION OF THE HOUSING AND BASKET, AND SUBSEWUENT CONNECTION OF SAID BASKET AND HOUSING. 